What language must the person maintaining the listening watch on channel 13 be able to speak?

The requirement for the person maintaining the listening watch on channel 13 to be able to speak English is rooted in international maritime communication protocols. Channel 13 is designated as a DSC (Digital Selective Calling) and VHF maritime safety channel, primarily used for ship-to-ship and ship-to-shore communications in distress situations.

English is recognized as the international language of maritime communication under the International Maritime Organization (IMO) standards. This means that effective communication in emergencies, navigational assistance, and coordination of rescue efforts must occur in English to ensure that all parties understand each other, regardless of their home countries or native languages.

The other languages listed may be spoken by various mariners, but they do not hold the same international recognition and standardization in maritime safety communications as English does. Hence, fluency in English is essential for the person on watch to fulfill the role effectively and ensure safety at sea.